1. Field of the Invention
The present invention relates generally to ink cartridges, ink supply systems, comprising such ink cartridges, and to an image recording apparatus comprising such ink supply systems. More specifically, the present invention is directed towards ink cartridges, ink supply systems, and image recording apparatus in which the inside of such ink cartridges is bought into air communication with the atmosphere to reliably supply ink from the ink cartridge to the image recording apparatus.
2. Description of Related Art
A known inkjet image recording apparatus is configured to feed a recording medium, e.g., a sheet of paper. The inkjet image recording apparatus includes a carriage configured to reciprocate in a direction perpendicular to a direction in which the recording medium is fed, and a recording head mounted on the carriage. The recording head includes a plurality of nozzles through which ink droplets are ejected toward a recording medium to form a desired image on the recording medium. A known ink cartridge is configured to be removably mounted to the known inkjet image recording apparatus. The known ink cartridge includes an ink chamber configured to store ink therein, and an ink supply portion. When the known ink cartridge is mounted to the inkjet image recording apparatus, ink is supplied from the ink chamber to the recording head via the ink supply portion.
Known inkjet image recording apparatus may include an on-carriage-type apparatuses or an off-carriage-type apparatus. The on-carriage-type inkjet recording apparatus includes a case having a mounting portion on which the ink cartridge is removably mounted. The case is positioned on the carriage. When the ink cartridge is mounted on the mounting portion of the case, ink is supplied from the ink cartridge to the recording head. The off-carriage-type inkjet recording apparatus includes a case positioned in a portion of the inkjet recording apparatus other than the carriage. The case includes a mounting portion on which the ink cartridge is removably mounted. The off-carriage-type inkjet recording apparatus further includes a tube connected to the case and the recording head. When the ink cartridge is mounted on the mounting portion of the off-carriage-type inkjet recording apparatus, ink is supplied from the ink cartridge to the recording head via the tube.
If gas dissolves in the ink which is in the ink chamber, the gas may turn into bubbles in the recording head or the tube when the ink is supplied to the inkjet recording apparatus, and the bubbles may clog the nozzles. When such bubbles clog the nozzles, ink may not be properly ejected from the nozzles. To prevent gas from dissolving in the ink, the ink may be deaerated, or the pressure in the ink chamber may be reduced, or both.
In the known ink cartridges, the ink chamber is brought into air communication with the atmosphere before or when the ink cartridge is mounted to the mounting portion. Nevertheless, when the ink cartridge is mounted to the mounting portion, the ink chamber may be brought into fluid communication with the recording head or the tube via the ink supply portion before the ink chamber is brought into air communication with the atmosphere. When this occurs, air or ink in the recording head or the tube may flow back into the ink chamber if the pressure in the ink chamber is reduced. Backflow of air or ink may cause the ink meniscus in the nozzles to be altered.
Another known ink cartridge, such as the ink cartridge described in Japanese Patent Publication Number JP-A-2003-300330, may prevent the ink meniscus from being altered. This known ink cartridge includes an ink chamber, an ink supply portion which includes an ink supply valve therein, an atmosphere communication opening through which the ink chamber is brought into air communication with the atmosphere, and a film which seals the atmosphere communication opening. Another known inkjet image recording apparatus, such as the inkjet recording apparatus also described in Japanese Patent Publication Number JP-A-2003-300330, includes a mounting portion having a protrusion and a pipe. The mounting portion is configured to receive the above-described another known ink cartridge, and each of the protrusion and the pipe extends from the bottom of the mounting portion in a direction parallel to a direction in which the ink cartridge is inserted into the mounting portion. When the ink cartridge is mounted to the mounting portion, the protrusion perforates the film, such that the ink chamber is brought into air communication with the atmosphere via the atmosphere communication opening, and the pipe applies a force to the ink supply valve, such that ink is supplied from the ink chamber to the inkjet recording apparatus via the ink supply portion. Because the protrusion extends further from the bottom of the mounting portion than the pipe, the protrusion perforates the film before the pipe applies the force to the ink supply valve. Therefore, the ink chamber is brought into air communication with the atmosphere before the ink chamber is brought into fluid communication with the inkjet recording apparatus via the ink supply portion.
Similarly, yet another ink cartridge, such as the ink cartridge described in Japanese Patent Publication Number JP-A-2005-238576, also includes an ink chamber, an ink supply portion, and an atmosphere communication opening, and yet another known inkjet image recording apparatus, such as the inkjet image recording apparatus also described in Japanese Patent Publication Number JP-A-2005-238576, includes an accommodating mounting portion having a first pipe and a second pipe. The ink supply portion includes an ink supply valve therein, and the atmosphere communication opening includes an atmosphere communication valve. The mounting portion is configured to receive the yet another known ink cartridge, and each of the first pipe and the second pipe extends from the bottom of the mounting portion in a direction parallel to a direction in which the ink cartridge is inserted into the mounting portion. When the ink cartridge is mounted to the mounting portion, the first pipe applies a force to the atmosphere communication valve, such that the ink chamber is brought into air communication with the atmosphere via the atmosphere communication opening, and the second pipe applies a force to the ink supply valve, such that ink is dispensed from the ink chamber to the inkjet recording apparatus via the ink supply portion. Because the first pipe extends further from the bottom of the mounting portion than the second pipe, the first pipe applies the force to the atmosphere communication valve before the second pipe applies the force to the ink supply valve. Therefore, the ink chamber is brought into air communication with the atmosphere before the ink chamber is brought into fluid communication with the inkjet recording apparatus via the ink supply portion.
Still another known inkjet image recording apparatus is configured to determine the amount of ink remaining in an ink cartridge based on the number of ink droplets which previously were ejected from the nozzles or the number of times the recording head previously was cleaned. Specifically, the inkjet image recording apparatus counts the number of ink droplets ejected from the nozzles or the number of times the recording head is cleaned. When the amount of ink remaining in the ink cartridge decreases to a predetermined amount of ink, the inkjet recording apparatus indicates that a user should replace the current ink cartridge with a new ink cartridge. For example, the inkjet image recording apparatus may include a lamp which alternates between an illuminated state and a non-illuminated state when the amount of ink remaining in the ink cartridge is less than or equal to the predetermined amount of ink. When the ink cartridge is removed from the mounting portion and the amount of ink in the ink cartridge is greater than the predetermined amount of ink, and the previously removed ink cartridge again is mounted to the mounting portion, the inkjet recording apparatus is reset to a state corresponding to when the amount of ink in the ink cartridge is at a maximum value. When this occurs, the amount of ink in the ink cartridge does not correspond to the amount of ink which the inkjet recording apparatus determined is in the ink cartridge. Consequently, the inkjet recording apparatus may fail to timely indicate that the amount of ink in the ink cartridge is less than or equal to the predetermined amount.
To prevent the inkjet recording apparatus from failing to timely indicate that the amount of ink in the ink cartridge is less than or equal to the predetermined amount, still yet another ink cartridge, such as the ink cartridge described in Japanese Patent Publication Number JP-A-2000-135796, includes a predetermined portion which still yet another known inkjet image recording apparatus, such as the inkjet recording apparatus also described in Japanese Patent Publication Number JP-A-2000-135796, is configured to detect. Specifically, the inkjet image recording apparatus is configured to perforate or bend the predetermined portion of the ink cartridge when the ink cartridge is mounted to the mounting portion. When the inkjet recording apparatus detects the predetermined portion of the ink cartridge, the inkjet recording apparatus determines that the mounted ink cartridge is an ink cartridge which has not previously been mounted to an inkjet recording apparatus. After the inkjet recording apparatus perforates or bends the predetermined portion of the ink cartridge, the image recording apparatus cannot detect the predetermined portion of the ink cartridge.
Nevertheless, if the ink cartridge includes separate portions for allowing the ink chamber to be in communication with the atmosphere and for indicating that the ink cartridge has not previously been mounted to an inkjet recording apparatus, the ink cartridge may be more complex and the amount of ink which the ink cartridge may store therein may be reduced.